The emerald ash borer is taking a deadly toll in Michigan, and not just on trees.

Weakened ash are toppling and shedding limbs with greater frequency since a tree-killing bug stowed in cargo from Asia to Detroit 16 years ago, experts say. And they're hitting people — with tragic results.

“It’s just that we have a lot of ash trees in the state and a high proportion have died, and you run the possibilities. It gets a little scary that way,” said Deborah McCullough, a Michigan State University entomologist specializing in ash borer research.

Against still high odds, people are dying, Detroit News research shows. At least eight have been killed by falling trees or limbs in Michigan this year — five by ash. The other deaths involved oaks: one just this month north of Lansing; two motorcyclists in May in Barry County.

The tally of fatalities is anecdotal. There is no comprehensive registry in Michigan of injuries from dead or diseased ash trees. The News identified casualties through media reports, site visits, satellite images, photographs, arborists and witnesses. Untold more people have been injured or escaped near misses.

FILE - The trunk of a dead ash tree shows canker-like scarring from invasive Emeral Ash Borer, Wednesday, Aug 23, 2017. The Emerald Ash Borer burrows under the bark and kills the tree.(Photo11: John L. Russell, Special to The Detroit News)

On Oct. 1, the day the motorist was killed near Lansing, the state lifted its 16-year-old quarantine against transporting campfire hardwoods, conceding the effort was too late to stop the bug’s invasion.

Other victims include a South Lyon landscaper who was crushed when a large portion of an ash tree broke May 2. A 90-year-old Kent County man’s moving car was flattened a day earlier by a domino of falling ash trees. And in southwest Michigan that same day, an ash crushed one property owner — a short distance and almost exactly one year after another homeowner was similarly killed.

The culprit is an invading beetle, green and iridescent: theemerald ash borer.

"Right now in some areas, we are at the peak of the bell curve (for collapsing ash),” said John Bedford, pest response program specialist with the state Department of Agriculture and Rural Development.

'They're all dead'

Jim Green sits astride his quadrunner on a recent Sunday afternoon along White Temple Road in southwest Michigan, talking to his brother, Tom. Their brother-in-law died up the road last May. Accounts vary; they end the same.

Robert Wright, 73, was crushed May 1 by a falling tree in the woods behind his home near Vandalia, about 30 miles north of the Indiana border in Cass County.

The Green brothers believe it was an ash. The tree fell either while his attention was turned to a different downed tree, or while attempting to cut the second tree. Google Earth shows vast areas of standing dead ash in this mix of farms, fields and hardwood forests.

“They are all dead; I haven’t seen a live one,” Jim Green says. Limbs from several dead ash extend over a nearby dirt road he’ll use to get home. “I duck when I drive under them.”

The next day 190 miles away, a worker in Oakland County was killed by a tree. A landscaper heard a crack. He found a large section of the hardwood had fallen on a 36-year-old foreman in Independence Township, causing massive head injuries. Gusts up to 65 mph were reported.

The same day, a postal carrier delivering mail in Oakland County was injured by “ash snap,” common enough to have a name. The tree broke in South Lyon in half about 25 feet above the ground during a heavy storm. The carrier reportedly could speak but not move. Emergency workers used chainsaws to free him.

Destruction of the forest

Scientists call the half-inch emerald ash borer the most destructive and economically costly forest insect to invade the U.S. It has killed more than 30 million ash trees in southeast Michigan alone, with the potential to wipe out more than 700 million statewide, according to the state and national Emerald Ash Borer Information Network.

The trees are popular park and streetside plantings. They shadow trails for hikers and skiers, riversides for anglers. Its hardwood is used for furniture, flooring, cabinets, tool handles and sporting equipment. Ash was the crack behind Mickey Mantle’s bat.

Probably just a few borers stowed here in wooden crates or pallets, scientists say. Science calls it an “extinction event,” the ash trees’ version of the asteroid that wiped out dinosaurs.

The borers’ destruction was first found in 2002 in Canton Township, ironically named for the Chinese city. Asian ash evolved defenses. U.S. ash had none.

By 2004, the beetle munched its way to the tip of the Lower Peninsula, starving trees of food and water. The jump to the Upper Peninsula was identified two years later. Only four U.P. counties — Iron, Ontonagon Gogebic and Luce — have not reported infestations, possibly because there are fewer people.

Today, 35 states, D.C, and five Canadian provinces are affected. Rhode Island, Maine and Vermont, and New Brunswick and Nova Scotia, Canada, were added this year.

Green, white and black are the most common ash in Michigan. They account for about 25 percent of trees. All are vulnerable, some more so.

There are an estimated $8.7 billion ash trees throughout North America. The cost of treating and removing just 50 percent of landscape ash in urban areas could exceed $10.5 billion by 2019, a report co-authored by McCullough, the MSU researcher, found. Including suburbs, costs nearly double.

“In terms of trees falling in the forest, we are approaching the peak of that bell curve (in areas),” McCullough said.

Borers burrow beneath bark. Nutrients are cut off. The trees die of starvation and thirst. They can look alive but their wood is brittle. The trees fall or drop limbs without warning. It’s one reason tree cutting is the most dangerous job in the U.S., ahead of deep-sea fishing, according to the U.S. Bureau of Labor Statistics.

Once infested, ash stands can approach 100 percent mortality within six to eight years. At first, symptoms are not obvious. Later, mortality accelerates. It’s called a “synchronized death.”

“All of a sudden you see it everywhere in a given area. It appears it all happened at once,” said Bedford, the state pest expert.

A year ago, an influential scientific group placed five types of eastern U.S. ash on its “Red List of Threatened Species.” The trees are now categorized as “critically endangered,” one step from extinction, by the International Union for Conservation of Nature.

Both Bedford and McCullough emphasized the devastation is not the same everywhere, just as not all hardwoods in Michigan are the same. Maple, oak, birch, beech, hickory and others persist in various mixes. (Four west Michigan counties — Allegan, Muskegon, Oceana and Ottawa — are also quarantined against hemlock transport due to another Asian invasive, hemlock woolly adelgid).

Odds of being killed by a tree are very long. There are 10 million people in Michigan. That puts the number of tree deaths this year just over 1 in a million, same as when at least eight Michiganians died last year in similar circumstances, The News found. The chances are about the same as being hit by lightning, according to the National Weather Service. By contrast, odds of winning the recent $1.5 billion Mega Millions jackpot were one in 300 million.

'We heard it crack'

The past few years have been “especially” problematic, said RoNeisha Mullen, senior communications specialist with DTE Energy Co.

“As these (ash) trees become diseased and weakened, they're at great risk of falling on DTE power lines and electric equipment,” she said.

Arborists recommend removing diseased ash before they become too frail or die. The cost can mean the difference between a few hundred dollars to more than a thousand by a service. A thinning canopy is one indicator. Healthy trees can be treated annually against the borers.

Michigan’s invasive pest monitors are essentially admitting defeat. On Oct. 1, a quarantine regulating in-state transportation of ash and other campfire hardwoods was lifted. In doing so, Michigan joined several states in deciding the effort to slow ash borers no longer made sense; the insect was virtually everywhere.

“Based upon research, it’s likely it was in Michigan 10-15 years before it was even identified (near Detroit),” said Gina Alessandri, director of the state’s Pesticide and Plant Pest Management Division, in a statement ending the quarantine.

Infestations, death and disintegration are not uniform; a particular region might have forest stands in all stages. The heaviest destruction is in the southern portion of the Lower Peninsula, extending through Central and northern Michigan in various concentrations. The Upper Peninsula trails, but heavy infestations are found even there.

Vic Foerster, a consulting arborist in West Michigan, favored the hardwood quarantine.

“We know what we are dealing with, with ash borer and other invasives. It’s the ones we don’t know about that worry us,” Foerster said.